The present invention relates to a food preservative and a process for producing the same, and more particularly, to a food preservative to inhibit the propagation of bacteria by the aid of a vegetable alkaloid and to a process for producing the same.
It is known that horse radish for Sushi functions as a preservative because it contains sinigrin (a vegetable alkaloid), which, on decomposition by the enzyme myrosinase, becomes mustard oil (allyl isothiocyanate), which exhibits the antibacterial action. It is also known that garlic contains allicin (C.sub.6 H.sub.10 OS.sub.2), which has the antibacterial action. It is also known that .epsilon.-polylysine, which is an amino compound formed from L-lysine through the peptide bond between the .alpha.-carboxyl group and the amino group at the .epsilon. position, is effective in inhibiting the propagation of lactic acid bacteria, Escherichia coli, and Staphylococcus aureus. Hence, it is used as a food additive. In general, .epsilon.-polylysine is highly effective and easy to use; however, there are some foods for which it is not necessarily effective. Edible meat is an examples of them.
There are a large variety of vegetable alkaloids, some of which are toxic and others are edible. The vegetables that yield edible alkaloids include red pepper (capsanthin), common ginger root (zingerone and shogaol), pepper (chavicine), horse radish (sinigrin), mustard (sinaibin and sinigrin), and garlic (allicin). They are all known as spices. Extracting vegetable alkaloids from spices is not economical, except for garlic. Garlic yields a large amount of large bulbs capable of easy processing; however, it suffers the serious disadvantage of giving off a characteristic odor, and the production of allicin is accompanied by this odor. Garlic derives its odor and pungent taste from garlic oil, which contains allyl sulfide, allyl disulfide, allylpropyl disulfide, and allyl trisulfide. These sulfides give off the characteristic odor when they are decomposed into disulfide and sulfur dioxide by the alkali in garlic. This decomposition is accompanied by the formation of alliin (C.sub.6 H.sub.11 NO.sub.3 S), and alliin is subsequently decomposed into allicin (C.sub.6 H.sub.10 OS.sub.2) by the enzyme alliinase. In other words, alliin dominates allicin in garlic, and hence it is difficult to extract allicin alone. They cannot be separated completely, and the characteristic odor is unavoidable.